Experiments will be performed to obtain evidence that muscle end-plate acetylcholinesterase, end-plate acetylcholine receptors, resting membrane potential, and chloride conductance are normally maintained by trophic factor(s) moved by axonal transport and released from nerve. The trophic factor(s) involved will be partially purified in order to determine if there are multiple trophic factors influencing muscle properties and/or if individual trophic factors influence several muscle properties. We will attempt to raise antibody to each of these partially purified trophic factors in order to demonstrate that each of these factors is physiologically relevant by showing that the in vivo administration of anti-factor antibody causes denervation-like changes in the appropriate muscle properties.